Links in tabs of the labels index pages ends with `.html`
It seems the links in the tabs of the Labels index pages (e.g. https://gitlab.com/groups/gitlab-org/-/labels, https://gitlab.com/gitlab-org/gitlab-ce/labels) end with an .html
extension:
Most probably introduced by https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/21965. /cc @dzaporozhets